I've heard of mice eating wire insulation and causing all kinds of problems in our cars.
But, it always happens to the other guy, right?
Wrong...this time anyway.
Had a check engine light come on, read codes 3 & 13.
Took it in, initial diagnosis was air mass sensor. Put a new one in, didn't fix it.
Eventually found that mice had eaten through wire behind the battery, had even eaten a hole through the plastic shroud between the engine and firewall.
I have never seen any sign of mice in my garage...even have two cats that spend most of their time out there...old cats though, with little energy anymore...probably think the mice are just friendly little critters that come in to play with them now and again.